Family, twin, and adoption studies have clearly established a genetic contribution to the etiology of schizophrenia. The current project is to continue to expand our cohort of multiplex families using a sibling pair search for a gene for schizophrenia and to pursue the hypothesis that one or more major gene defects is responsible for the inheritance of schizophrenia. Based on simulation studies we previously estimated the need for at least 500 nuclear families with definite schizophrenia in a minimum of two siblings to accurately detect a major gene linkage by either lod score or sib pair analyses. This is particularly powerful when a small number of genes, rather than one is involved in the mechanism for inheritance, when the mode of inheritance is not known, and when the diagnostic boundaries for illness are unclear. Are we willing to provide the complete approved protocol to the NIH to be abstracted for inclusion in various publicly available databases (e.g; PDQ, Rare Disease, Clinical Trials Research)? No